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Commit 3650b57f authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

timer: Further simplify the SMP and HOTPLUG logic 



Remove one CONFIG_HOTPLUG_CPU #ifdef in trade for introducing one
CONFIG_SMP #ifdef.

The CONFIG_SMP ifdef avoids declaring the per-CPU __tvec_bases storage
on UP systems since they already have boot_tvec_bases.

Also (re)add a runtime check on the base alignment -- for the paranoid
amongst us :-)

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/fdd2d35e169bdc554ffa3fe77f77716298c75ada.1427814611.git.viresh.kumar@linaro.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 8def9060

kernel/time/timer.c

+15 −8
Original line number Diff line number Diff line
@@ -101,7 +101,6 @@ struct tvec_base { 
 */

struct tvec_base boot_tvec_bases;

EXPORT_SYMBOL(boot_tvec_bases);

static DEFINE_PER_CPU(struct tvec_base, __tvec_bases);



static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
@@ -1038,6 +1037,8 @@ int try_to_del_timer_sync(struct timer_list *timer) 
EXPORT_SYMBOL(try_to_del_timer_sync);



#ifdef CONFIG_SMP

static DEFINE_PER_CPU(struct tvec_base, __tvec_bases);



/**

 * del_timer_sync - deactivate a timer and wait for the handler to finish.

 * @timer: the timer to be deactivated
@@ -1591,12 +1592,10 @@ static void migrate_timers(int cpu) 
	spin_unlock_irq(&new_base->lock);

	put_cpu_var(tvec_bases);

}

#endif /* CONFIG_HOTPLUG_CPU */



static int timer_cpu_notify(struct notifier_block *self,

				unsigned long action, void *hcpu)

{

#ifdef CONFIG_HOTPLUG_CPU

	switch (action) {

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:
@@ -1605,18 +1604,24 @@ static int timer_cpu_notify(struct notifier_block *self, 
	default:

		break;

	}

#endif



	return NOTIFY_OK;

}



static struct notifier_block timers_nb = {

	.notifier_call	= timer_cpu_notify,

};

static inline void timer_register_cpu_notifier(void)

{

	cpu_notifier(timer_cpu_notify, 0);

}

#else

static inline void timer_register_cpu_notifier(void) { }

#endif /* CONFIG_HOTPLUG_CPU */



static void __init init_timer_cpu(struct tvec_base *base, int cpu)

{

	int j;



	BUG_ON(base != tbase_get_base(base));



	base->cpu = cpu;

	per_cpu(tvec_bases, cpu) = base;

	spin_lock_init(&base->lock);
@@ -1643,8 +1648,10 @@ static void __init init_timer_cpus(void) 
	for_each_possible_cpu(cpu) {

		if (cpu == local_cpu)

			base = &boot_tvec_bases;

#ifdef CONFIG_SMP

		else

			base = per_cpu_ptr(&__tvec_bases, cpu);

#endif



		init_timer_cpu(base, cpu);

	}
@@ -1657,7 +1664,7 @@ void __init init_timers(void) 


	init_timer_cpus();

	init_timer_stats();

	register_cpu_notifier(&timers_nb);

	timer_register_cpu_notifier();

	open_softirq(TIMER_SOFTIRQ, run_timer_softirq);

}